1. Field of the Invention
This invention relates to automotive fuel systems, and in particular to an apparatus and method for modifying a fuel tank to accept an in-tank fuel pump when the tank was not originally designed for use with such an in-tank pump or when an additional in-tank pump is required.
2. Description of the Related Art
Modern automobiles using electronic fuel injection systems utilize a fuel pump mounted inside the fuel tank of the vehicle (hereinafter referred to as an “in-tank pump”) to pick up fuel from the tank and deliver it to the engine. Older automobiles, which typically used carburetors to mix fuel with incoming air, did not use in-tank pumps, but instead relied on mechanical or electric pumps mounted outside of the fuel tank.
Recently, it has become increasingly popular among automobile enthusiasts to modify an older car, such as a muscle car from the 1960s or 1970s, by installing a modern fuel injected engine in place of the original power plant, or by replacing the original carburetor with an aftermarket fuel injection system. This type of modification can produce a vehicle with increased performance, improved fuel efficiency and better emissions while retaining the look and feel of the classic muscle car. One problem frequently encountered during the course of making such a modification is the difficulty of mounting an in-tank fuel pump in a fuel tank not originally designed to accept an in-tank pump.
In other applications, it may be advantageous to add an in-tank pump to a fuel system in order to supplement a pre-existing fuel pump. The additional pump may be mounted in parallel to the pre-existing pump and used on-demand to provide additional fuel volume as needed by the engine. The pre-existing fuel pump may be either an external pump or an in-tank pump, such as an original equipment in-tank pump. If the pre-existing fuel pump is an original equipment in-tank pump, it then becomes necessary to modify a fuel tank which was originally designed for use with a single in-tank pump in order for it to accept a second in-tank pump.
In either of the above applications, the problem of mounting an in-tank pump in an existing tank is further complicated by an additional requirement that baffling be added to the tank along with the pump. In-tank fuel pumps need to be surrounded by baffles that prevent all of the fuel from sloshing away from the pump during turns or other abrupt maneuvers. These baffles act to retain a column of fuel over the pump's fuel pickup so that the pump never draws air into the fuel injection system, which can lead to fuel starvation and/or vapor lock. (Carburetors, because they have reserve fuel in their fuel bowls, are more tolerant of momentary fuel deprivation and do not require similar baffles around the fuel pickups.)
In order to add an in-tank pump and baffle to the existing fuel tank, a hole must first be cut into the top of the tank through which the pump and baffle can be inserted. It is advantageous that the hole not be any larger than necessary, and therefore, the baffle should be able to fit through the smallest diameter hole possible (a hole not much larger than the diameter of the pump). The baffle, therefore, should be of thin material, or of a material that can be radially compressed in order to fit though the hole and then allowed to expand once inside the tank. Fuel tanks also vary substantially in depth. In order for the baffle to fit in a wide variety of different tanks, it should be able to be height-adjustable to correspond to the depth of virtually any tank.
What is needed is an apparatus and method for mounting an in-tank pump in a fuel tank, the apparatus including sufficient baffling to retain a column of fuel over the fuel pickup in order to provide an uninterrupted fuel supply to the engine. The apparatus should be adaptable to fit a variety of fuel tanks of differing depths.